What are the main reasons against the Windows Registry?

Question

If i want to develop a registry-like System for Linux, which Windows Registry design failures should i avoid?
Which features would be absolutely necessary?
What are the main concerns (security, ease-of-configuration, ...)?

I think the Windows Registry was not a bad idea, just the implementation didn't fullfill the promises. A common place for configurations including for example apache config, database config or mail server config wouldn't be a bad idea and might improve maintainability, especially if it has options for (protected) remote access.

I once worked on a kernel based solution but stopped because others said that registries are useless (because the windows registry is)... what do you think?

Answer 1

the first one that come to my mind is somehow you need to avoid orphan registry entries. At the moment when you delete program you are also deleting the configuration files which are under some directory but after having a registry system you need to make sure when a program is deleted its configuration in registry should be deleted as well.

Answer 2

If you must have a single repository, at least use a proper database so you have tools to restore, backup, recover it etc and you can interact with it without having a new set of custom APIs

Answer 3

I once worked on a kernel based solution but stopped because others said that registries are useless (because the windows registry is)... what do you think?

A kernel-based registry? Why? Why? A thousand times, why? Might as well ask for a kernel-based musical postcard or inetd for all the point it is putting it in there. If it doesn't need to be in the kernel, it shouldn't be in. There are many other ways to implement a privileged process that don't require deep hackery like that...

If i want to develop a registry-like System for Linux, which Windows Registry design failures should i avoid?

• Make sure that applications can change many entries at once in an atomic fashion.
• Make sure that there are simple command-line tools to manipulate it.
• Make sure that no critical part of the system needs it, so that it's always possible to boot to a point where you can fix things.
• Make sure that backup programs back it up correctly!
• Don't let chunks of executable data be stored in your registry.

Answer 4

IMHO, the main problems with the windows registry are:

• Binary format. This loses you the availability of a huge variety of very useful tools. In a binary format, tools like diff, search, version control etc. have to be specially implemented, rather than use the best of breed which are capable of operating on the common substrate of text. Text also offers the advantage of trivially embedded documentation / comments (also greppable), and easy programatic creation and parsing by external tools. It's also more flexible - sometimes configuration is better expressed with a full turing complete language than trying to shoehorn it into a structure of keys and subkeys.

• Monolithic. It's a big advantage to have everything for application X contained in one place. Move to a new computer and want to keep your settings for it? Just copy the file. While this is theoretically possible with the registry, so long as everything is under a single key, in practice it's a non-starter. Settings tend to be diffused in various places, and it is generally difficult to find where. This is usually given as a strength of the registry, but "everything in one place" generally devolves to "Everything put somewhere in one huge place".

• Too broad. Its easy to think of it as just a place for user settings, but in fact the registry becomes a dumping ground for everything. 90% of what's there is not designed for users to read or modify, but is in fact a database of the serialised form of various structures used by programs that want to persist information. This includes things like the entire COM registration system, installed apps, etc. Now this is stuff that needs to be stored, but the fact that its mixed in with things like user-configurable settings and stuff you might want to read dramatically lowers its value.